Most significant cold snap in decades for southern Ontario

Thursday, May 4, 2017, 8:18 PM - The month of May begins on an unseasonable note for southern Ontario, with an extended stretch of below-seasonal temperatures in the region's forecast.

Much of the south of the province is also in line for a prolonged rainfall event, with parts of the southwest expected to see rainfall totals surpass 100 mm in some areas.

But that system will be accompanied by a cold snap. And by "cold snap," we not only mean single-digit daytime highs, there's also a fair chance many people in southern Ontario are likely to see a few snowflakes in their forecast by Sunday.

"The cold snap, which is expected to last five days, will be one of the most significant spans of cold weather Toronto has seen in May," The Weather Network meteorologist Tyler Hamilton says.

KEEP ON TOP OF ACTIVE WEATHER: Visit the Alerts section of the website

"The record for the most single-digit days in a row in May is five, and that was back in May of 1974," Hamilton adds. "Currently, we're forecast to get five days of single digits, making it one of the most prolonged cold periods in history."

The cooler temperatures are the product of a few factors -- namely, a cut-off upper-level low system developing in the southeastern U.S., coupled with cool, modified Arctic air plummeting south across the Prairies late week.

"[B]y Friday and Saturday, those systems phase together," Hamilton explains. "The highest terrain in southern Ontario could see some flakes over the weekend -- though this is still subject to change a bit."

Orangville, Gravenhurst, Huntsville may see a potential for accumulating snow through the weekend, and the Greater Toronto Area, too, shouldn't be surprised if flakes fall near the end of the weekend.